hmc5883_i2c.cpp

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/**
 * @file HMC5883_I2C.cpp
 *
 * I2C interface for HMC5883 / HMC 5983
 */

#include <px4_platform_common/px4_config.h>
#include <drivers/device/i2c.h>
#include <drivers/drv_mag.h>
#include <drivers/drv_device.h>

#include "hmc5883.h"

#define HMC5883L_ADDRESS        0x1E

device::Device *HMC5883_I2C_interface(int bus);

class HMC5883_I2C : public device::I2C
{
public:
    HMC5883_I2C(int bus);
    virtual ~HMC5883_I2C() = default;

    virtual int read(unsigned address, void *data, unsigned count);
    virtual int write(unsigned address, void *data, unsigned count);

    virtual int ioctl(unsigned operation, unsigned &arg);

protected:
    virtual int probe();

};

device::Device *
HMC5883_I2C_interface(int bus)
{
    return new HMC5883_I2C(bus);
}

HMC5883_I2C::HMC5883_I2C(int bus) :
    I2C("HMC5883_I2C", nullptr, bus, HMC5883L_ADDRESS, 400000)
{
    _device_id.devid_s.devtype = DRV_MAG_DEVTYPE_HMC5883;
}

int
HMC5883_I2C::ioctl(unsigned operation, unsigned &arg)
{
    int ret;

    switch (operation) {

    case MAGIOCGEXTERNAL:
        return external();

    case DEVIOCGDEVICEID:
        return CDev::ioctl(nullptr, operation, arg);

    default:
        ret = -EINVAL;
    }

    return ret;
}

int
HMC5883_I2C::probe()
{
    uint8_t data[3] = {0, 0, 0};

    _retries = 10;

    if (read(ADDR_ID_A, &data[0], 1) ||
        read(ADDR_ID_B, &data[1], 1) ||
        read(ADDR_ID_C, &data[2], 1)) {
        DEVICE_DEBUG("read_reg fail");
        return -EIO;
    }

    _retries = 2;

    if ((data[0] != ID_A_WHO_AM_I) ||
        (data[1] != ID_B_WHO_AM_I) ||
        (data[2] != ID_C_WHO_AM_I)) {
        DEVICE_DEBUG("ID byte mismatch (%02x,%02x,%02x)", data[0], data[1], data[2]);
        return -EIO;
    }

    return OK;
}

int
HMC5883_I2C::write(unsigned address, void *data, unsigned count)
{
    uint8_t buf[32];

    if (sizeof(buf) < (count + 1)) {
        return -EIO;
    }

    buf[0] = address;
    memcpy(&buf[1], data, count);

    return transfer(&buf[0], count + 1, nullptr, 0);
}

int
HMC5883_I2C::read(unsigned address, void *data, unsigned count)
{
    uint8_t cmd = address;
    return transfer(&cmd, 1, (uint8_t *)data, count);
}